Field of the Invention
The present invention relates to a radiation image photographing system, and in particular to a radiation image photographing system including a radiation generator installed on a round visit cart or a transportable radiation generator.
Description of the Related Art
As a device for photographing a radiation image which is an alternative to a conventional film/screen, a photostimulable phosphor plate or the like, a flat panel detector (FPD) cassette has been developed. Specifically, as illustrated, for example, in FIG. 2 to be described later, the FPD cassette is configured in such a manner that a plurality of radiation detecting elements 7 is arrayed two-dimensionally (in a matrix), radiation that has passed through an object is converted, by each radiation detecting element 7, into image data D in accordance with its intensity, and the image data D are read.
When radiation is emitted to the conventional film/screen or the photostimulable phosphor plate multiple times, problems such as double exposure and multiple exposure occur, and videography of an object cannot be performed. On the other hand, with the use of the FPD cassette, the read image data D can be saved in a storage unit 23 (refer to FIG. 2 to be described later) within the device, whereby the videography such as kymography of an object can be performed.
As used herein, the kymography means photography that is performed in such a manner that, for example, radiation is emitted to a chest of a patient that is an object multiple times, and as illustrated, for example, in FIG. 10, radiation images (also referred to as frame images or the like in the context of kymography) of a lung field R of the patient in respective time phases T (T=t0 to t6) are acquired. Then, for example, the respective radiation images are further analyzed in a recent attempt to apply the analysis to diagnosis. In the present invention, the videography is not limited to the above-mentioned kymography, and may take on any aspect as long as radiation is emitted to an object multiple times or emitted to an object continuously to photograph a plurality of radiation images.
Meanwhile, in some cases, the videography with the use of the FPD cassette is performed in a well-equipped photographing room. In a case where, for example, a patient cannot come to the photographing room, the videography is likely to be performed in such a manner that a round visit cart (for example, refer to JP 2003-310595 A and JP 2014-204783 A) on which the FPD cassette and the radiation generator or the like are installed is brought into a hospital room in a hospital or the like, and radiation is emitted to a photographing site such as a chest of a patient that is an object multiple times.
Alternatively, the videography is sometimes performed in such a manner that a transportable (i.e., generally referred to as portable) radiation generator 57* illustrated, for example, in FIG. 11 is brought into the hospital room. Although only a main body part of the transportable radiation generator 57* is illustrated in FIG. 11, at the point of use, the transportable radiation generator 57* is fixed to a stand, a leg or the like (not illustrated) and used in this state.
In a case where, for example, the videography is the kymography, the photography of the respective radiation images illustrated in FIG. 10 is performed in such a manner that radiation is emitted from the radiation generator to a patient that is an object for about 20 seconds, during which the patient has to maintain a posture. Therefore, in a case where the patient is unaccustomed to the kymography, the patient does not understand how long he/she has to maintain the posture after the emission of the radiation is started, and the patient is likely to be put under a lot of stress.
In addition, a photographer such as a radiation technologist needs to pay attention by, for example, continuously monitoring whether the posture of the patient is appropriately maintained during the photography. Unlike in the case where the kymography is performed in the photographing room, however, in a case where the round visit cart or the like on which the radiation generator or the like is installed is brought into the hospital room to perform the photography, a person or the like other than the patient is likely to enter an emission field of the radiation. Therefore, the photographer needs to pay further attention so that, for example, the person or the like other than the patient does not enter the emission field of the radiation, and the photographer is likely to be put under a lot of stress.
Furthermore, since the radiation is invisible, the person other than the patient cannot determine, for example, whether the emission of the radiation has been finished. Therefore, for example, another patient in the same hospital room cannot understand whether he/she can come by near the radiation generator, and a helper, a caretaker or the like cannot understand whether he/she can touch the patient that is the object. Consequently, they are subjected to the restriction on the behavior or suffer from the continuous tension for a considerable time, whereby they are also likely to be put under a lot of stress.
As described above, particularly in a case where the FPD cassette and the round visit cart or the like are brought into the hospital room to perform the videography such as the kymography, attention needs to be paid to the fact that the photographing environment is different from that for the photography in the photographing room in the hospital or the like in that the person other than the patient as well as the patient and the photographer such as a radiation technologist is likely to be near the photographing place.